first decide the requirement and then join the sheets.
If you want to show the each source as different view and not joined any dataset then go with data blending option and create it.
One way to do it is to create multiple data sources by connecting multiple times to the same Excel workbook - first to one sheet, then to the next sheet and so on... It's not an attractive way to do it, but as long as the sheets have no columns in common on which to join them, I don't have a better idea. You can then use each data source in one Tableau sheet.